Is that similar to the cones used in pottery ovens?
Honestly I am not familiar with them. I know they are stands to hold pieces off the floor of the oven so they heat and cool evenly?
But alloy metals can be put in Crucibles and heated to the exact temp in a furnace where one melts before the other which separates them. The metal that requires a higher temp to melt will form a “slag” on top of the more molten pool of metal under it. That slag can be scraped off the top to remove it from the lower temp pool of metal.